Rich Saik (by way of Brian K. Short KE7GH ) wrote:
> I was reading in your web page of the "getter" technique. That
> sounds like a reasonable approach, but I was wondering if you can
> speak for that approach yourself. Also, do you have any idea how
> long one would have to apply filament voltage in order to drive off
> the gassing problem? Are we talking about a matter of minutes or a
> couple of hours, or what?
With a 3-500Z, years.
The gettering agent is not near the filament, it is coated on the anode.
The only way to getter a 3-500Z is to get the anode hot to the point of
showing some color. It can be done by biasing the tube into conduction
at low anode voltage, butb that isn't easy.
The SB-1000's did have a history of plate transformer insulation
failure.
Pull the tube and see if the fuses dump.
> I did take the time to ohm across the transformer, but I didn't see
> anything earth-shattering (direct shorts, etc.).
Won't work.
> Of course, that does not say what would
> happen at high voltage conditions. I thought about disconnecting the
> transformer outputs, insulating them well and applying power. Then,
> if fuses weren't blown, I could reconnect each output separately and
> then see what happened. That seems to be a compatible approach with
> the one described in the web page.
That'll work.
73 Tom
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